The bug happens when we have two or more rows merged in the first column and programmatically, we make the rowDetails for the first row visible, the merged cells of the first column stay merged and are over of the rowDetails, hiding a part of the Row Details:

Hi Team,

We have a large-scale WPF application that uses the Telerik WPF RadGridView across multiple screens. We are experiencing significant memory growth issues. Upon deep analysis of the memory dump, we observed that the RadGridView continuously pushes DispatcherPriority items into the Dispatcher queue. We also noticed an internal timer within the RadGridView that appears to be active even after the control is no longer visible.  We would like to understand how to completely detach and stop this internal timer once the control is removed from the screen, and why the RadGridView keeps pushing DispatcherItem entries into the Dispatcher queue.

Telerik Version : 2017.2.503.45

When using an INotifyCollectionChanged (like ObservableCollection<T>), RadGridView's data engine subscribes to the CollectionChanged event of the bound collection.

It seems that the WPF views are recreated when you connect to a running remote desktop session or switch the user to a session where the corresponding WPF app is already opened. This creates new instances of all controls, but no unload or another disposal event happens. In this case, the logic that subscribes to the CollectionChanged event again is triggered for the new RadGridView, but the old one never detaches from the event. This causes a memory leak.

If you connect to the session multiple times, the CollectionChanged handler will be attached multiple times leading to a memory leak.

To work this around, set the ItemsSource of RadGridView to null in the SystemEvents.SessionChanged static event.

private void SystemEvents_SessionSwitch(object sender, SessionSwitchEventArgs e)
{
    if (e.Reason == SessionSwitchReason.SessionLock)
    {
        BindingOperations.ClearAllBindings(this.RadGridViewFixed);
    }
}

Currently, the delimiter is hardcoded to ",". Add a setting that allows changing this and also synchronizing it with the current culture of the system.

In the case where some of the columns are hidden and all of the columns' display indexes are changed, applying grouping could result in some of the cells from the columns that have custom CellTemplate to not receive it.

To work this around, you could manually change the widths of the columns by iterating the Columns collection as shown below:

foreach (var column in this.GridView.Columns)
{
    GridViewLength length = column.Width;

    if (length.IsAbsolute)
    {
        column.Width = new GridViewLength(length.Value + 0.00001);
    }
}

NullReferenceException occurs when the the automation peers creation for the rows goes over 10,000 peers (the MaxCachedPeersSize setting of the GridViewDataControlAutomationPeer). The exception occurs only when the 'record' modifier is used in the class definition. For example:

public record class MyClass(int Id)
{
}

The exception stacktrace is:

System.NullReferenceException: 'Object reference not set to an instance of an object.'
peer was null.
Telerik.Windows.Controls.GridView.dll!Telerik.Windows.Automation.Peers.GridViewDataControlAutomationPeer.ClearPeer(Telerik.Windows.Automation.Peers.DataItemAutomationPeer peer)   Telerik.Windows.Controls.GridView.dll!Telerik.Windows.Automation.Peers.GridViewDataControlAutomationPeer.GetOrCreateItemPeer(object item, int index) Line 288 C#  Telerik.Windows.Controls.GridView.dll!Telerik.Windows.Automation.Peers.GridViewRowAutomationPeer.FindDataItemAutomationPeer(System.Collections.Generic.List<System.Windows.Automation.Peers.AutomationPeer> childPeers) Telerik.Windows.Controls.GridView.dll!Telerik.Windows.Automation.Peers.GridViewRowAutomationPeer.GetChildrenCore() 

.

To work this around use the "class" modifier instead of "record". For example, instead of:

public record class MyClass(int Id)
{
}

Use:

public class MyClass
{
    public int Id { get; set; } 
}

 Or alternatively, increase the MaxCachedPeersSize value.

When adding a button cell as below, if the button cell is selected the button doesn't work when tapping it.

<telerik:GridViewDataColumn Header="Config"
                            DataMemberBinding="{Binding .}" IsReadOnly="True">
    <telerik:GridViewDataColumn.CellTemplate>
        <DataTemplate>
            <!-- Adding telerik:TouchManager.TouchMode="None" solves the issue -->
            <telerik:RadButton HorizontalAlignment="Center" Style="{StaticResource MyButtonStyle}"
                               Margin="2" Padding="1" Width="Auto" Height="Auto"
                               Command="{Binding DataContext.ShowExtraConfigurationCommand, RelativeSource={RelativeSource AncestorType=Window}}"
                               CommandParameter="{Binding .}" ToolTip="Config">
                <telerik:RadGlyph Glyph="{StaticResource GlyphGear}"/>
            </telerik:RadButton>
        </DataTemplate>
    </telerik:GridViewDataColumn.CellTemplate>
</telerik:GridViewDataColumn>

As stated in the comment, adding the property below to the RadButton solves the issue.

telerik:TouchManager.TouchMode="None"

I have attached a sample project in which the error occurs, simply tap a button, close the MessageBox and tap the same button again. Thank you for your time!

If a RadDocking has its theme set to Windows 11 via the StyleManager.Theme attached property, placing a RadGridView inside (styled with a different theme, such as Office_Black, Summer, etc.) will cause its cells to look merged after performing an edit operation.

As a workaround, the RowHeight and the FontSize properties of the RadGridView instance can be used to resolve this.